Funchal has a mild mediterranean climate with even temperatures all year around. The climate can be separated into two main seasons: a rainier and slightly cooler season from October through March with average daily high temperatures ranging from 20 °C (68 °F) to 25 °C (77 °F) and a drier and warmer season from April through September with average daily high temperatures ranging from 21 °C (70 °F) to 26 °C (79 °F). Humidity levels remain constantly high at about 70%. Sea temperatures range from a low of 18 °C (64 °F) in February–March to 24–26 °C (75 °F) in August–October.

Since the city rises from the sea up to altitudes of 800 meters on its northern slopes, it is quite common to experience cloudiness, fog and rain on those northern suburbs while clear skies remain nearer to the sea. Temperatures also tend to be slightly lower at the higher altitudes.

Early summer, especially June, tends to be quite infamous due to a phenomenon where persistent cloudiness covers the entire bay area of Funchal, locally nicknamed "Funchal's helmet". The length and severity of the rainy season varies greatly from year to year.